Spooling device



Oct. 23, 1945. DAVlDSON ET AL 2,387,245

SPOOLING DEVICE Filed July 12, 1943 5 Sheets-Sheet 1 mum-E 3 Oct. 23, 1945. 1-, 0. DAV|DSON ET AL 2,387,245

SPOOLING DEVICE Filed July 12, 1943 3 Sheets-Sheet 2 Z070! 'fiMm u $054: 'INVENTORS.

BY tr I ATTORN s Oct- 23, 1 T. o DAVIDSON ET AL 2,387,245

SPOOLING DEVICE Filed July 12, 1943 3 She ets-Sheet s C ATTORNEYS:

Patented Oct. 23, 1945 a SPOOLING DEVICE Trevor 0. Davidson, Milwaukee, and Roger Sherman Hoar, South Milwaukee, Wis., assignors to Bucyrus-Erie Company, South Milwaukee, Wis., a corporation of Delaware Application July 12, 1943, Serial No.'494,280 11 Claims. (01. 254-190) Our invention relates to new and useful improvements in spooling devices, primarily but not necessarily for cable-tool drills.

Such drills, per se, are well known.

In such drills a rope passes, from a winch drum on the main frame, around a heel sheave at or near the pivot of a spudding beam, thence under a sheave at the oscillating end of the spudding beam, thence over a sheave at the upper end of a mast and thence vertically downward into the hole which is being drilled in the ground. At the lower end of this rope is a string of percussion drilling-tools. The spudding beam is oscillated by a pitman, actuated by a rotating crank.

As the rope is payed out to lower the tools as the hole grows deeper, or is taken in to withdraw the tools for any reason, it' is desirable that the reach of rope from the winch-drum to the heel sheave shall move from side to ide, always in a plane perpendicular to the axis of the drum, spooling the lays of the rope evenly oil of or onto the drum; and that the heel sheave shall move from side to side and change its orientation, so as always to lie substantially in the plane defined by the two reaches of rope which run from this sheave.

Accordingly it is the principal object of our invention to devise a mounting for the heel sheave, such that the heel sheave will automatically thus move and thus orient itself, under the influence merely of the tension in these two reaches of rope.

In addition to our principal object, above stated, we have worked out a number of novel and useful details, which will be readily evident as the description progresses.

Our invention consists in the novel parts and in the combination and arrangement thereof, which are defined in the appended claims, and of which two embodiments are exemplified in the accompanying drawings, which are hereinafter particularly described and explained.

Throughout the description, the same reference number is applied to the same member or to similar members.

Figure 1 is a plan view of a dril1 embodying our invention.

Figure 2 is a. side elevation of the same drill.

In these two figures, the associated parts of the drill have been shown very schematically, and much of the drill (well known to the art) has been omitted.

Figure 3 is a slightly enlarged vertical section of the heel sheave, taken along the lines 3-3 of Figure 2.

Figure 4 is a side elevation of that sheave, to the same scale as Figure 3.

Figure 5 is a plan view of part of a drill embodying a second variant of our invention. The rest of the drill is the same as in Figure 1.

Figure 6 is a side elevation of the heel sheave and associated parts of Figure 5.

, Figure '7 is a diagram to indicate the eometrical basis for the mathematical analysis of the problem involved in our invention.

Figure Billustrates the coordinate system involved in that mathematical analysis.

Figure 9 illustrates the geometrical intersection of the two surface equations involved in my invention.

Referring now to Figures 1 and 2, we see that II is the main frame of a drill, supported by wheels l2, and during drilling by blocks l3.

The frame H supports a mast l4 (called derric in the art), a motor (not shown) the pulley of which is designated as l5, a winch It, a spudding gear l1, and associated driving connections, not numbered.

From the winch IS, a rope l8 runs around a heel sheave l9, thence under a spudding-sheave 20, thence over a sheave (not shown) at the top of the derrick l4, thence down tothe drilling tools (not shown).

' The spudding gear I1 is clutched to and unclutched from a driving connection with the motor l5, by means of a clutch (not shown).

The spudding-sheave 20 is mounted (preferably by means of an offset substantially vertical pivot 2|, preferably approximately in line with the upper reach of rope 18) on the free end of 'a spudding-beam 22, which in turn is pivoted on horizontal pivots 23 on the frame I l.

The spudding-beam is rocked u and down by the rotation of the spudding gear l1, acting through pitman 24.

The winch I5 is controlled by means of a conventional drive, clutch, brake, and hand-levers (not shown) The operation of all these conventional parts will be readily understood.

Heel sheave IQ is journaled for free rotation on a cylindrical bushing 25, which in turn is cored to slide freely, without turning, on bar 26, which extends transversely from one side of the drill to the other.

To prevent the bushing 25 from turning on the bar 26, the bushing must be keyed to the bar in some manner. As shown in Figures 3 and 4, this keying is accomplished by making square in crosssection both the rod and the hole in the bushing,

but other equivalent keyings could be substituted. In order to prevent the bushing from wobbling on the bar, both the bar and the hole in the bushing are curved in a circular arc. This curvature approaches sutficiently closely to the optimum curvature (to be hereinafter discussed) so as to be practically indistinguishable therefrom. The proper orientation of the plane'defined by the curved bar will also be discussed hereinafter, but considerabledeparture therefrom is permissible.

The second variant of our invention i shown in Figures 5 and 6, in which heel sheave 21 takes the place of heel sheave l9; and bar 28 (preferably now of circular cross-section) takes the place of bar 26; and carriage 29 takes the place of bushing 25. Carriage 29 i held to slide on bar 28, without wobbling, by means of rollers 30.

In this variant, bar 28 can have exactly the optimum curvature, namely that defined by the equations hereinafter set forth, rather than a plan circular arc; though here again the circular arc would be quite satisfactory for all practical purposes.

Turning now to Figure 7, we see a representation of winch-drum l6, rope lfl, heel sheave I9, and spudding-sheave 2| Mathematically, it is convenient to deal in points. Accordingly point H (which takes the place of the heel sheave I9) is the floating center of that sheave. We shall use the term mean surface of the winch to designate the cylindrical surface of the rope on the winch when the winch is half filled. Point D (which takes the place of winch I6) is a point moving along-an element of the mean surface of the winch, which element is defined by the line of tangency of a plane through point H (when that point is-in its mid position to that mean surface. Roughly it is the topmost element of the mean surface of the winch; although, if the winch were woundin a direction opposite to that shown, it

would be roughly the bottommost element. Point F (which takes the place of spudding sheave 20) is roughly the intersection of the extensions of those two reaches of rope l8 which are adjacent to sheave 20.

- Itis obvious from Figure '7 that point D could be conceived of as sliding along another line parallel to the axis of the drum, and that points H and F could be conceived of as located at other places near their respective sheaves, than the line and the points chosen, without introducing any error much more appreciable than that involved-in our original selection of this line and these points to define the broken line DHF. None of the approximations, utilized later herein, in-

troduce even so much error as this. Accordingly we may, in the claims, call the line along which D moves broadly the drum, rather than any particular line on the drum; and the point F the spudding sheave, rather than any particular point thereon; and the point H the floating sheave, rather-than the center thereof.

Turning now to Figure 8, the Z-axis is the line defined by the movement of point D. The origin, 0, is the mid-point of thatline. The X-axis extends from the origin through point F. The Y- axis extends, perpendicular to the other two axes, in the generaldirection'of point H, the coordinates (at, y, a) of which determine the equations of optimum curvature and orientation of the rod 26. i

' For convenience, we shall call the distance from the drum to the spudding sheave: 4'. And the width of the drum: 2a.

- Then the coordinates of extreme position of D, shown in Figure 8, are: 0, O, a. The coordinates of the mid point of H we shall call: .120, yo, 0. The coordinates of F, which is fixed are: r, 0, 0

It can be mathematically demonstrated that the optimum path for the moving point H is the intersection of the following two surfaces.

1. A circular cylinder, the axis of which is the Z-axis:

2. A parabolic cylinder, symmetrical with respect to the X-axis, and having its generating lines perpendicular to the XZ plane.

Turning to Figure 9, we see these two cylinders graphically illustrated. This figure is merely illustrative, and does not purport to be proportioned exactly in accordance with the specific value of the constants in the other figures.

The circular cylinder, the parabolic cylinder, and the path defined by their intersection, are all labeled in words on the figure. The three coordinate axes are also shown.

That part of the path which is utilized in our invention is a very small and substantially flat portion of the upper left-hand reach thereof.

It'can be mathematically demonstrated that the path of intersection is perpendicular to both HD and HF (see Figure '7). Hence a sheave I9 constrained so that its hub exactly follows this path would lie exactly in the plane'of the two adjacent reaches of rope I8; and a sheave constrained so that its hub follows substantially this path would lie substantially in that plane.

This path, within the range of actual travel of heel sheave I9, very closely approximates a plane parabola. The approximate location of the plane of this curve is determined as secant to the above defined circular cylinder, and as passing through that element (in the mathematical sense) of this cylinder which contains the mid location of the point H, and also as passing through an element of the cylinder lying two-thirds of the way along the surface of the cylinder from the first mentioned element to that element which contains the two extreme positions of the point H. Such plane may be roughly described as being substantially perpendicular to a mean'line DH.

The above-mentioned parabola, within the range of actual travel of heel sheave l9, closely approximates that circular are which has a fourpoint tangency with its apex. Accordingly we have chosen this circular are as the approximation to the ideal path for the moving point H.

Our invention can, of course, be used for a spoolin device on winches other than those of a cable-tool drill. Y

Having now described and illustrated two forms of our invention, we wish it to be understood that our invention is not to be limited to the specific form or arrangement of parts herein described and shown, except in so far as required by limitations in our claims.

We claim:

l. A spooling device, comprising: a first sheave; a fixed position drum; a floating sheave; and means, including a rope extending from the drum around the floating sheave and thence around the first sheave, constraining the floating sheave to follow a path which is substantially the curve of intersection between a circular cylinder, the equation of which is :v +y =xo +yo and a parabolic cylinder, the equation of which is z =2r(:vzco) the X-axis being a perpendicular dropped on the drum from the first sheave, the origin of coordinates being.the foot of this perpendicular, the Z-axis being the drum, the Y-axis extending perpendicular to the other two axes in the general direction of the floating sheave, the point 170,210, being one position of the floating sheave, and 1 being. the length of the perpendicular.

2. A spooling device, comprising: a first sheave; a fixed position drum; a floating sheave; and means constraining the floating sheave to follow such a path that, with a rope extending from the drum around the floating sheave and thence around the first sheave, the reach of rope from the drum to the floating sheave will always lie substantially in a plane perpendicular to the axis of the drum, and the floating sheavewill always lie perpendicular to its path and substantially in the plane of the two reaches of rope which extend from it: the constraining means comprising a properly curved and oriented rod; and a bushing for the floating sheave to rotate upon, said bushing having a central hole, curved to fit the rod, and keyed to the rod for sliding thereon but constrained against rotation thereabout.

3. A spooling device, according to claim 2, characterized by the fact that the rod and the hole in the bushing are polygonal in cross-section.

4. A spooling device, according to claim 2, characterized by the fact that the rod and the hole in the bushing are curved in a circular arc.

5. A spooling device, according to claim 2, characterized by the fact that the rod and the hole in the bushing are curved in a circular arc, and are polygonal in cross-section.

6. A spooling device, comprising: a first sheave; a fixed position drum; a floating sheave; a curved bar; a hollow bushing for the floating sheave, said bushing being externally shaped for a close rotational fit within the floating sheave, and being internally shaped for a close sliding fit about the bar, and being slidably keyed to the bar to prevent rotation thereabout; the sheaves, the drum, and the bar, being so relatively proportioned and positioned that a rope, extending from the drum around the floating sheave and thence around the first sheave, will be properly spooled onto and ofi of the drum.

7. A spooling device, comprising: a first sheave; a fixed position drum; a floating sheave; a curved bar, a polygonal cross-section; a hollow bushing for the floating sheave, said bushing being externally shaped for a close rotational fit with the floating sheave, and being internally shaped for a close sliding non-rotational fit about the bar; the sheaves, the drum, and the bar, being so relatively proportioned and positioned that a rope, extending from the drum around the floating sheave and thence around the first sheave, will be properly spooled onto and off of the drum.

8. A cylindrical sheave bushing, having a lengthwise curved hole of polygonal cross-section.

9. A sliding sheave assembly, comprising: the sheave; a curved bar; and a hollow bushing, externally shaped for a close rotational fit within the sheave, and internally shaped for a close sliding fit on the bar, and slidably keyed to the bar to prevent rotation thereabout.

10. A spooling device, comprising: a first sheave; a fixed position drum; a floating sheave; a carriage for the floating sheave; the floating sheave and the first sheave, in that order, being capable of spooling a line off of and onto the drum; and a track for the carriage, constraining the floating sheave to follow a path which is substantially the curve of intersection between a circular cylinder, having its axis along the drum, and a parabolic cylinder, the focal distance of which is equal to one half the distance between the first sheave and the drum, and the generating lines of which are perpendicular to the plane defined by the drum and by a perpendicular dropped on the drum from the first sheave.

11. A spooling device, comprising:

, cular cylinder, having its axis along the drum,

and a parabolic cylinder, the focal distance of which is equal to one half the distance between the first sheave and. the drum, and the generating lines of which are perpendicular to the plane defined bythe drum and by a perpendicular dropped on the drum from the first sheave; said track and carriage constraining the ax1e.of the floating sheave to tangency with said curve.

TREVOR O. DAVIDSON.

ROGERi SHERMAN HOAR.

a first, sheave; a fixed position drum; a floating sheave; 

